The increasing demand for microparts and products has prompted the industry to focus on more efficient ways to better supply such consumables. This continuous demand is pushed by consumers as well as industries that are relying more on smaller products with diverse applications. Metal forming processes are well known for displaying high productivity and better material utilization. Applying these forming technologies on the microscale level is significant for achieving parts with intricate geometries and configurations, which is an essential issue in such a scale, especially when high precision and tight tolerances are dominant factors.
To date, investigations of size effects on totality and formability in microforming applications are generally limited to tensile tests of thin sheets and few micro deep drawing and micro bulge forming studies. Formability during tensile tests has been simply characterized by elongation until failure. For the biaxial experiments, limiting drawing ratio and maximum bulge height have been used to characterize the formability during micro deep drawing and micro bulge forming respectively. This limited formability analysis is not sufficient to understand the size effect, which are known as the effects of miniaturization on microforming processes, on deformation and formability at the microscale. More detailed analysis of strain distributions and limiting strains during microforming of thin sheets is needed to be able to predict deformability limits for thin sheets and minimize trial and error runs that are conventionally performed to master the know-how of a micro-metal forming process. The consequences of such prediction are better optimization of process parameters and a reduced overall manufacturing cost.
In order to conduct the specified analysis, testing apparatus and equipment that will accommodate microscale testing is needed. Microscale testing by conventional testing equipment cannot demonstrate the degree of precision nor account for the effect which is considered minor at the macroscale level: such as friction which has proven to increase drastically as process miniaturization is increased. Forming limit diagrams (FLDs) are an effective tool for studying the formability of sheet metals at different strain conditions. The present invention relates to an integrated approach for investigating size effects and the formability of thin sheets for microforming applications.